1. Field of the Invention
The present invention relates to a blade position detection apparatus, and, more particularly, to a blade position detection apparatus for detecting breakage or wear of a high speed rotational blade of a dicing apparatus for cutting a groove along the street of wafer at the time of manufacturing semiconductors.
2. Description of the Related Art
It is an important factor to allow the quantity of a wafer work left from a groove cutting operation performed by a dicing apparatus to agree with a predetermined value.
In order to allow the quantity left from the operation of cutting wafer to agree with a predetermined value, the location of the Z-axis and the repetition of the location must be performed accurately and as well as the quantity of wear of the blade must be detected so as to be corrected.
The following two methods have been known to correct the quantity of the wear of the blade. First of all, a method has been known in which the blade is brought into contact with a machining table after a predetermined number of grooves have been cut in the wafer and then electricity is applied to the blade and the machining table so as to correct the blade. Another method has been known in which data (an empirical value) about the quantity of the wear of the blade is previously input as an automatic wear correction quantity to the dicing apparatus.
However, the former method encounters a problem that the blade can be damaged because the blade is brought into contact with the machining table, and what is worse, another problem arises in that the machining table is damaged. On the other hand, the latter method raises another problem in that the empirical value cannot be adapted to the variation of the quantity of the wear of the blade taken place depending upon the conditions such as the type of the wafer to be machined, the scattering of the blades and the quantity of cutting.